Low Prevalence of Mild Alpha-1-Antitrypsin Deficiency in Hospitalized COVID-19-Patients.

Introduction: Alpha-1-antitrypsin (AAT) has been shown to inhibit SARS-CoV-2 cell entry and suggested as a therapeutic agent for COVID-19. Furthermore, epidemiological association of high prevalence of Alpha-1-antitrypsin deficiency (AATD) and regional severity of COVID-19-impact has been hypothesized. In our study setting, the estimated prevalence rates of mild (PI*MZ, PI*SS or PI*MS) and moderate-to-severe AATD (PI*ZZ or PI*SZ) are high, 9% and 0.2%, respectively. Our primary aim was to examine the prevalence rate of AATD among hospitalized COVID-19-patients.

Methods: In this prospective observational study, enrollment occurred from December 2020 to January 2021 in two COVID-19-units at Skåne University Hospital, Lund, Sweden. Case definition was a patient hospitalized due to COVID-19. Patients were screened for AATD with PI-typing and if results were inconclusive, PCR for the S- and Z-genes were performed. Patients were categorized as severe or moderate COVID-19 and 30-day-mortality data were collected. The primary outcome was prevalence rate of AATD. The secondary outcome investigated association between presence of mild AATD and severe COVID-19.

Results: We enrolled 61 patients with COVID-19. Two patients out of 61 (3%) had mild AATD (PI*MZ) and none had moderate-to-severe AATD. 30/61 (49%) had severe COVID-19. Both patients with mild AATD developed severe COVID-19. Yet, presence of AATD was not significantly associated with severe COVID-19 (p=0.24).

Conclusion: Mild AATD (PI*MS or PI*MZ) was rare in a small cohort of hospitalized patients with COVID-19 in a study setting with a high background prevalence of AATD.